CCS involves capturing the CO2 emitted by fossil-fuelled power stations, compressing and transporting it by pipeline, and burying it in deep underground repositories. Previously CCS was one of the principal hopes for mitigating greenhouse gas emissions from electricity generation, but the technology has turned out to be more complicated and expensive than previously believed. While tiny pilot plants have been built, the proposed CCS systems are still a many years, possibly decades, from becoming commercially available.

Meanwhile, renewable energy technologies have been advancing rapidly.

A joint research group from the university's School of Electrical Engineering and Telecommunications, Centre for Energy and Environmental Markets (CEEM) and Institute of Environmental Studies (IES) and has used conservative cost projections in computer simulations to compare the economics of fossil fuel scenarios using hypothetical coal power plus CCS with scenarios of 100 per cent renewable electricity based on commercially available technologies.

In each scenario, for each hour of the year 2010, the researchers – PhD candidate Ben Elliston and his supervisors Associate Professors Iain MacGill (CEEM) and Mark Diesendorf (IES) – balanced electricity demand and supply to achieve the same reliability from renewable electricity as in the existing system.

Using prices of the technologies and fuels projected to 2030 by the Australian Bureau of Resources and Energy Economics and wide ranges of possible future carbon prices and CCS prices, they find that only for a few, apparently unlikely combinations of these prices could the coal with CCS scenarios compete economically with 100 per cent renewable electricity.

The researchers also compared gas-fired power stations plus CCS with 100 per cent renewable electricity. While the gas scenario could possibly be competitive at current gas prices, its domestic price is actually increasing rapidly.

“The research confirms that policies pursuing very high penetrations of renewable electricity, based on commercially available technologies, offer a reliable, affordable and low risk way to dramatically cut emissions in the electricity sector. There is no need to invest in expensive, unproven, high-risk, fossil fuel technologies”, Professor Diesendorf added.